Phenolic resin foam laminated sheets have high heat insulation performance, flame retardant property, and heat resistance among foamed plastic-based heat insulating materials, and thus widely used as construction materials and materials for general industrial applications. When airtightness of heat-insulating layers would be secured under high temperature environments which are particularly severe conditions to withstand for heat-insulating materials used for roof of buildings etc., there is a case where a sealant or the like is separately applied in between heat-insulating materials, or between a heat-insulating material and a member such as a frame, and therefore it takes a lot of labor during construction. Also, in a composite board obtained by joining a phenolic resin foam laminated sheet and other members and/or in a heat-insulating structure where a finishing material such as mortar and/or resin is laminated on a surface of a phenolic resin foam laminated sheet applied without any gaps on the same plane, there are problems that the phenolic resin foam laminated sheet causes a change in dimensions, and therefore warp occurs, and/or cracks occur in the finishing material.
In Patent Literature 1, a method of manufacturing a phenolic resin foam laminated sheet is proposed, in which a plurality of partially cured foams are overlaid via spacers in a hot-air curing furnace and postcure is conducted at a predetermined temperature and wind speed.